Adjustable dental engine bracket aem



(No Model.) 2 Sheets-Sheet 1.

Q J. E. STANTON. ADJUSTABLE DENTAL ENGINE BRACKET ARM.

No. 513,214. v Patented Jan. 23, 1894.

UNITED STATES PATENT OFFICE.

JERE E. STANTON, OF BOSTON, MASSACHUSETTS.

ADJUSTABLE DENTAL-ENGINE BRACKET-ARM.

SPECIFICATION forming part of Letters Patent No. 513,214, dated January 23, 1894.

To all whom it may concern.-

Be it known that I, JERE E. STANTON, of Boston, in the county of Sufiolk and State of Massachusetts,.have invented a new and useful Dental and Surgical Bracket and Arm, of which the following, taken in connection with the accompanying drawings, is a specifica My invention consists of an improved jointed bracket and arm for holding and transmitting power to a rotary, flexible toolbearing spindle for dentists or surgeons use, the apparatus being adapted to be supported by the wall and so constructed as to be capable of being folded down compactly against the wall, or held in a great variety of positions, or Varied instantly in length of reach, without removing or breaking the continuity of the endless belt or cord which carries the power from the motor to the tool-bearing spindle at the outer end of the arm. As the arm is varied in length or changed in posi tion about its joints, the slackof the endless belt that would otherwise be formed, is automatically taken up by a compensating device in a manner fully describedlhereinafter in detail.

Referring to the accompanying drawings:- Figure 1. is a side elevation of a bracket and arm embodying my invention. Fig. 2. is a plan view on a larger scale of the inner part of the apparatus. Fig. 3. is a longitudinal, upright section thereof, taken through the center ofthe belt compensating device; and

Fig. 4. is a transverse sectional view on a still larger scale, taken in the plane of as m, Fig. 3.

A is the stationary part of the apparatus which is screwed, or otherwise firmly secured, to the wall or to any convenient, upright support. The part Ais provided with the lugs or ears a, to which, bymeans of the pivotal bolts a in line with each other, is jointed the bracket, consisting of the similarly shaped pieces, A A, an upper and a lower, rigidly held together by suitable. connections. Each piece A terminates at its outer ends, in a sleeve or collar A in which is firmly held the vertical rod 0.

B is a block through which the rod 0 passes, said block being firmly secured to the upper piece A in the position shown in Fig. 3. This block is provided with the forwardly project- Application filed June 19. 1893. Serial No. 478,064. on model.)

ing lugs 1) between which is jointed at h the tube H.

K is a brace having'at its upper end the bifurcated piece K, which embraces the top of the rod O'and is pivoted at cthereto. The lower end ofthe brace is jointed at k to a sleeve H which is movable longitudinally over the tube H and capable of being clamped in any position thereon by means of the set screw H The tube H forms a hollow socket within which the rod I is adapted to slide, said rod being clamped at any desired position by means of the set screw H in the tube H. The rod I terminates at its outer end in the angle connection I in which is also firmly secured the second rod 1 preferably at right angles to the rod I. The rod 1 is adapted to hold in its upper end a support R ofany approved construction having'bearings for the arbor M, provided with the pulley M. The arbor M gives motion tothe flexible toolholding spindle (not shown) which is secured thereto, the part of the apparatus above and beyond the arm I being of ordinary con struction common to dental and surgical engines. The source of motive power is in the drawings represented by an electric motors from the driving wheel of which the endless belt N passes along suitable guiding pulleys presently to be described, and around the spindle-driving pulley M. It will be seen that by this construction of jointed parts the arm may be moved in alldirections, having free lateral movement about a vertical axis passing through the pivotal bolts a a, and having a vertical movement about the pivot at h. When it is desired to change the position of the arm in a vertical plane, the thumb-screw H in the sleeve H is loosened, the arm placed at the required angle, and the screw H again tightened. In this manner the arm may be clamped at any desired angle, either horizontal, as shown in Fig. 1, or pointing upward or downward, or folded compactly down against the wall as indicated by the dotted lines. Furthermore the arm may be varied greatly in length by pushing in or drawing out the rod I within the tube H, the thumb screw H serving to clamp the rod at any desired position. While the length of the arm and its position may thus be varied at will, I have provided an automatic compensating device whereby the endless powertransmitting belt N instantly adapts itself to the varying conditions and requires no attention on the part of the operator in shifting the arm about, but drives the arbor M equally well in all positions of the arm.

As shown in the drawings, the endless belt N runs around the motor pulley, over the pair of sheave pulleys E under the pair of similar pulleys P and under the third pair of pulleys I and around the pulley M. The guiding pulleys P are journaled on the crosspiece P which is preferably connected with a sleeve P, capable of being clamped at any desired position on the arm H, by means of the set screw P The pair of guiding sheave pulleys I are journaled, one on each side of the angle connection I. The cross-piece E, to each end of which one of the pair of guiding pulleys E is journaled, is secured tothe upper end of a rod. E which moves easily up and down in the vertical tube L, said tube being rigidly held in the block B. The tube L has the longitudinal slot Z through which projects the pin e fixed in the rod E near the lower end thereof.

D D is a pair of sheave pulleys journaled one on each side of the block B.

F is a weight suitably guided to move up and down, being hung by the cords f fastened at one end to the top of the weight. These cords pass over the pulleys D one on each side, and are secured at the other end to the pin e. As represented in Fig. 4., the weight F is provided with lugs F which move over opposite sides of the plate L on the back of the tube L. The parts are so arranged, and

the weight F is such, that whenever a slack would occur in the endless belt N, either by shortening up the arm or changing its angular position, or both, the weight F falls, drawing up the rod E in the tubeL and lifting up the pulleys E under the belt N, thus taking up theslack. As the arm is varied in length by pulling out or pushing in, the weight moves up and down, keeping the belt N at all times at the proper tension.

Dotted lines in Fig. 1. show the weight n its lowest position, and the pulleysE in thelr uppermost position, corresponding to the shortest reach of the arm.

Instead of employing a weight-operated compensating device for taking up the slack of the belt, the movement of the rod L bearing the sheave pulleys E could readily be effected by means of a spring acting in any desired manner thereon. In any event, whether by weight or spring, the actuating power tends to keep the pulleys E firmly pressed against the cord or belt with sufficient force to keep the belt constantly tight, so that whenany slack would occur in changing the position of the arm, this slack is immediately taken up automatically by the movement of the rod L bearing the pulleys thereon. One pulley might obviously be employed instead of a pair, to accomplish the same purpose.

I claim- A suitably supported, tool-holding arm, adjustable in length and provided with a tooldriving pulley, in combination with a motor drive-wheel, an endless power-transmitting belt or cord, suitably arranged guiding pulleys, a vertically movable rod having mounted thereon one or more pulleys engaging with said belt, and a properly guided operating weight connected by cord and pulley with said rod, as and for the purposes set forth.

In testimony whereof I have signed my name to this specification, in the presence of two subscribing witnesses, on this 10th day of February, A. D. 1893.

' J ERE E. STANTON.

Witnesses:

ALBERT E. LEACH, M. T. LEACH. 

